Air conditioning system



Feb 24, 1942.

A. B. NEWTON AIR CONDITIONING SYSTEM Original Filed May 6, 1938 L o c m m m T T A m I m P 2 P M q M 2 E O 29 E o "M flsu. o 1.. 1 :1: T T H w. .J v w 4 5% u v 0. m

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inventor Alwizn B. Newioru 'IIIIIIIIIIIIIIIIJ VIIIlIII/IIIIII/IIIIII/IIIIIIIIIIIII/IIIIIIIIII V Patented Feb. 24, 1942 AIR CONDITIONING SYSTEM Alwin B. Newton, Minneapolia'lvlinm, assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Original application May 6, 1938, Serial No. 206,411. Divided and this application August 5, 1939, Serial No. 288,609

3 Claims.

This application is a division of my application Serial No. 206,411, filed May 6, 1938, for Air conditioning system.

This invention relates in general to air conditioning orrefrigeration and is particularly concerned with the provision of an expansion valve arrangement for an evaporator of the type employing a plurality of parallel passes.

In the air conditioning art it is desirable to utilize direct expansion cooling coils in a conditioner for cooling the air being passed to the space, as these coils are very compact and efficient., In larger systems it is desirable to utilize instead of a single cooling coil a direct expansion type heat exchanger which is formed of a plurality of parallel passes, for thereby decreasing the pressure drop. Direct expansion coils of this type present a problem of distributing the liquid refrigerant equally to the various passes, for if the refrigerant is not equally distributed, either some of the passes will become flooded, and perthe liquid refrigerant when the heat exchanger operates as an evaporator are unnecessary, and in fact are undesirable as they create an additional pressure drop within the system.

It is an object of this invention to provide'a distributor device for a multiple pass heat exchanger which acts to distribute properly the liquid refrigerant to the various passes when the heat exchanger is operating as an evaporator,

and which automatically permits by-passing of refrigerant around the distributor restrictions when the heat exchanger is operating as a condenser. Another object isthe provision of a distributor device for a multiple pass unit which utilizes the velocity of the liquid refrigerant leaving the expansion valve for aiding in the distribution of the liquid refrigerant to the various passes.

Other objects of the invention will become When the heat exchanger is operating as a condenser, the restrictors used for distributing apparent from the following description and the appended claims. V r

For a full disclosure of this invention reference is made to. the following detailed description and to the accompanying drawing, in which:

Fig. l is a diagrammatic illustration of a re versible cycle refrigeration system utilizing a vention, and Fig. 2 is an elevation in section showing the I multiple pass heat exchanger in a conditioning chamber, and provided with the expansion valve and distributor arrangement of the present inexpansion valve and distributor arrangement for the direct expansion coils.

Referring to Fig. 1, reference character I indicates an air conditioning chamber having a fresh air inlet 2, and a return air inlet 3 which communicates with a space to be conditioned 4. The

discharge end of the chamber I is connected to a fan 5 which acts to draw air through the chamber I and discharge it through suitable duct means into the space 4. Located within the chamber I is a heat exchange device generally indicated as 6, this heat exchange device being adapted to operate as an evaporator for cooling the space, or as a condenser for heating the space. The heat exchange device 6 preferably is formed of a plurality of separate cooling coils or refrigerant passes I, 8, 9, and Ill. The right-- hand ends of, these coils are connected to a suitable header I I while the left-hand ends of these coils are connected to a combined expansion valve and distributondevice indicated as I2.

Referring now to Fig. 2, this figure indicates the construction of the combined expansion valve and distributor device It. Referring to the expansion valve portion of this device, this valve may be of the same type shown in my copending application Serial No. 192,818, filed Feb. 26, 1938. This expansion valve may comprise a diaphragm casing I3 which houses a diaphragm structure formed of diaphragms I4 and I5 and a connecting member I6. The diaphragm or bellows I4 is sealed to the lower surface of the diaphragm casing I3 and the lower end thereof is closed by means of a cup member IT. The bellows I5. is

similarly sealed to the upper end of casing I3, andits open end is closed by means of a cup member I8. Both the bellows I4 and the bellows I5 are sealed as by soldering to the member I6 so as to provide a unitary fluid tight device. The cup member I I is provided with a fitting I9 which is connected by apipe 20 to a fitting 2| located v on the header II. A passage 22 is provided within the fitting I9 for placing the interior of the bellows I4 into communication with the interior of the header II. The pressure within bellows I4 is therefore equal to the pressure within this header. Also located within the fitting 2| is a thermostatic bulb 23 which is connected to 'a capillary tube 24 located within the pipe 28, this tube 24 being attached to the fitting I9 in a manner to communicate with a passage 25 in this fitting. This passage 25 is connected by means of a coiled tube 25 located within the bellows I4 to the interior of the bellows I5. The bulb 23 contains a suitable volatile fill which preferably is the same as the refrigerant used in the system. The arrangement just described therefore will cause a pressure to exist within the bellows I which is indicative of the temperature in the header II, while the pressure within the bellows I4 is equal to the pressure within said header.

Connected to the member I5 is a rod 21 which extends upwardly through the cup member I8, this rod being threaded at its upper end as shown and carrying a nut 28 engaging a spring 29 which is supported by means of a spring retainer 30. A sealing bellows 3| is provided for preventing the escape of vapor from the bellows I5. With the arrangement just described it will be apparent that upon an increase in pressure within the header II the bellows I4 will expand and the bellows I5 will contract, while upon an increase in temperature at bulb 23 the pressure within bellows I5 will increase thereby causing expansion of this bellows and contraction of the bellows I4. The bellows I4 and I5 therefore act in' opposition and the vertical position assumed by the connecting member I5 is an indication of the degree of superheat of the refrigerant at the fitting 2|.

The member I5 is provided with a pin 32 which cooperates with a lever arm 33 extending through an opening 34 into the valve chamber 35. This lever is pivoted to the valve chambercasing at 35 and carries a valve member 31' cooperating with a valve port 38 located in a nipple 39. A spring 48 is provided for urging the lever 33 in a direction tending to maintain the valve member 31 against the valve port 38. In operation, liquid refrigerant enters at 4| and passes through port 38 to the distributor device 42. If the amount of superheat of the refrigerant leaving the coils I, 8, 9, and III should increase, the pressure within bellows I5 will increase, this causin g downward movement of the member l5, ,and due to engagement of pin 32 with lever 33 the valve member 31 will be moved away from port 38 to increase the supply of liquid refrigerant to the coils. Conversely, upon decrease in the amount ,of superheat, the member I5 will move downwardly, thereby permitting valve member 31 to approach port 38 under the action of spring 48. By adjusting the nut 28 any desired degree of superheat may be maintained.

Referring now to the distributor device 42, this device consists of a member 43 having a chamber 44, this device being secured to the valve casing in a manner to cause the chamber 44 to register with the opening. in nipple 39. The member 43 is also provided witha plurality of restricted radial passages 45 which lead from the chamber 44 to openings 45 which are adapted for connection with the coils of the heat exchange device 5. It will be understood that a restricted passage 45 and connection 46 is provided for each of the coils of the heat exchange device. It will be noted that the nipple 39 is formed to provide a venturi and that the chamber 44 is in direct alignment with the valve port 38, so that the stream of liquid passing through the valve is discharged into the chamber 44 at high velocity. This high velocity discharge of refrigerant into the chamber 44 causes the liquid refrigerant to become a homogeneous mixtur of liquid and gas within this chamber and to pass through the restricted passages into the coils I, 8, 9, and I0. Due to this action of refrigerant within the chamber 44, both the gaseous and liquid refrigerant will be divided equally between the various coils. This arrangement therefore provides for the passing of the proper amount of liquid refrigerant to each coil and thereby prevents the flooding of one coil and the starving of another.

Each of the passages or connections 46 communicates through a passage 41 with a chamber 48 formed between the member 43 and a cap member 49. This chamber 48 is connected to a discharge connection 58. Each of these passages 41 is also provided with a ball valve member 5| which is urged against its seat by means of a spring 52 located within a recess 53 located within the cover member 49. The purpose of the passages 41 and the valve members 5| is to permit the. passage of refrigerant from the coils I, 8, 9 and I8 into the outlet connection 50 when the coils I, 8, 8 and II) are acting as condensers. This arrangement avoids the necessity of passing the liquid refrigerant through the restricted pas sages 45 when the system is operating as a heating system. The operation of the distributor device 42 will become apparent as this description proceeds.

Referring now to the remainder of the refrigeration system, reference character indicates a compressor which is connected by a di charge line 68 and branch lines BI and 52 with three-way changeover valves 63 and 64. These three-way valves are each provided with pipe connections A, B, and C and are controlled electrically by means of solenoid pilot valves. The solenoid pilot valve 53a of valve 63 and the solenoid pilot valve 64a of valve 64 are controlled by means of a summer-winter switch 18. This switch includes a switch arm II cooperating with contacts 12 and I3. During the summer tl-e switch arm II is moved into engagement with contact I3 which completes a circuit from the line wire I4 to the solenoid 53a and through wire I5, contact I3, and switch arm II to line wire I6. At this time, the switch arm II is out of engagement with contact 12 and therefore the solenoid 64a is deenergized. This position of the switch I8 causes the valve 53 to place its connections A and C into communication while blocking ofi connectionB, and also causes valve 54 to place its connections B and C into communication while blocking off its connection A. During the winter, the switch arm II is moved into engagement with the switch arm 12 which deenergizes the solenoid 53a and energizes the solenoid 84a. This causes the three-way valves 63 and 64 to assume-their opposite positions.

Assuming now that switch I8 is in the summer position, that is, switch arm II engages contact 13, the solenoid 63a will be energized while the solenoid 6 4a is deenergized. With the valves in the positions caused by this position of switch 18, compressed refrigerant flowing from the compressor through the line 68 will pass through pipe 6i into the three-way valve-53, leaving this valve through connection C and passing through line 91 into the heat exchanger 98 which now acts as a condenser. At this time, the port A of valve 64 is closed which prevents entry of compressed refrigerant into this valve, and also the connection refrigerant leaving valve member 31 will flow at very high velocity through the passage 39 into the chamber 44 of the distributor 42. This high velocity jet of refrigerant upon striking the walls of chamber 44 will form a homogeneous mixture of liquid and evaporated refrigerant due to the turbulence created by the impact of the high velocity jet. This now thoroughly mixed mixture of liquid and gaseous refrigerant will now flow through the radial passages 45 to the respective cooling coil passes and will flow from these passes into header II. The refrigerant in passing through the cooling coil passes becomes evaporated, the evaporated refrigerant being collected by header II and flowing .into the valve 64 through its connection C. The refrigerant will then flow from this valve through connection B and through pipes 65 and 61 to the inlet of the compressor. 7,

When the switch 10 is actuated so that the switch arm H engages contact 12, the three-way valves 63 and 64 will change in position for reversing the flow of refrigerant through the system. Now compressed refrigerant flowing from the compressor through line 60 will pass through pipe 62 into the valve 64 through connection A and will leave this valve through connection C passing into the header II. The compressed gaseous refrigerant will flow from the header ll into passes 1, 8, 9 and wherein it condenses to liquid. The liquid refrigerant will now flow from the passes into the distributor device 42.

However, instead of passing through the restricted passages 45 of this device, the refrigerant will by-pass these restricted passages, flowing through the passages 44 past the check valves into the The liquid refrigerant will flow chamber 48. from this point through the pipe I06 and check valve l0! into the receiver I08. From this receiver the refrigerant will flow through lines I09 and 19a into the expansion valve 1 l0 and from this expansion valve into the heat exchanger 98 which now acts as an evaporator. The refrigerant will now evaporatein the heat exchanger 98 and the evaporated refrigerant will flow through pipe 91 to the connection C of .the three-way valve 63 and will flow from this valve 63 through connection C and pass through pipes 66 and 61 to the inlet of compressor 55.

From the foregoing description, it will be apparent that the present invention provides an improved distributor device for multi-pass evaporators which acts to utilize the velocity of the refrigerant resulting from its passing through the expansion valve for mixing the refrigerant into a homogeneous mass and which distributes homogeneous turbulent mass thereby insuring that each pass of the evaporator receives its share of liquid and gaseous refrigerant. It will also be apparent from the foregoing description that the present invention additionally provides an improved distributor device for reversible cycle systems which acts to cause by-passing by th refrigerant of the restricted passages in the distributor when the system is operating on the heating cycle.

While the invention has been. shown in a system in which only one heat exchanger is of the air cooled multi-pass type, it will be obvious that the invention is equally applicable to systemsin which both heat exchangers are of this type. In such case each heat exchanger would be provided with a distributor device as disclosedherein.

While I have shown and described a preferred form of the invention, it will be apparent that many modifications can be made without departing from the scope of the invention. It is desired therefore to be limited only by the scope ,of the appended claims.

I claim as my invention:

1. In a refrigeration system, in combination, an evaporator comprising a plurality of parallel passages for refrigerant, an expansion valve, a

distributor device associated with said expansion valve, said distributor device comprising a relatively small chamber, means forming a venturi for conveying refrigerant from said expansion valve into said chamber, said venturi increasing the velocity of the refrigerant so as to discharge it into the chamber in a manner to create turbusaid chamber and means for providing communithe refrigerant to the evaporator passes from this cation between said passes and said chamber.

2. In a refrigeration system, in combination, an evaporator comprising a plurality of parallel passages for refrigerant, an expansion valve, a distributor device associated with said expansion -valve, said distributor device comprising a relatively small chamber, means forming a venturi for. conveying refrigerant from said expansion valve into said chamber,'said venturi increasing the velocity of the refrigerant so as to discharge it into the chamber in a manner to create turbulence in said chamber sufficiently to prevent segregation of gaseous and liquid refrigerant in said chamber, and means for providing communication between said passes and said chamber,

.said last means comprising a plurality of restricted channels communicating with said chamben.

3. In apparatus of the character described, in combination-means forming a valve chamber, means forming a fluid distributing chamber associated therewith, means forming a valve port communicating with said first chamber and having a restricted throat connecting said port directly with said second chamber, the connection between said port and second chamber being relatively short and straight.

ALWIN B. NEWTON. 

